Preparation of amino triazoles



inwvhich Bis an alkylnoycloalkyl onaryl radical.

.asole,

Patented Aug. 14, 1945 UNITED STATES PATENT .o-FFI 2,382,156 PREPARATION OF 'rm zoLEs Donald W; Kaiser, Riversidahflonn, assignor to, American "Oyanamid company New. York, N. Y., acorporation of Maine v v .NoDrawing. Application-May,1:;1944, Serial No. 536,019" I h Claims. I .(Cl. 260%36'5) This invention relates to. a new method of preparing amino triazoles, more particularly to the preparation of B-amino-LZA-triazoles.

' "I have discovered that when 3-ureido-.1,2 ,4-

.tr'iazoles are 'heated'in .a suitable liquid reaction medium comprising water and an acid .or alkali, these compounds are hydrolyzed ,to form 3- amino-'1,,2,4 -.triaz dles having the, following structural Iormu'la'z, 1.

Most of. the compounds of :the ,presentin vention are kno'wn. The lower members, .such as :methyl, are very water-soluble, :but :theFhigher members are less soluble. whey-lure easily soluble in aqueous solutions rot'alkalis and acids. The compounds are weak bases and form salts with strong acids. In general. they are soluble in organic solvents, such as Cellosolve (monoethyland acid-takes aplace tat about 50 to 125 0; or higher :and requires from about 1 to about hours for complete hydrolysis depending upon the particular temperature used. The hydrolysis of 3-ureid0--1;2,-4-triazoles with-alkali appears to be more rapid than acid hydrolysis and is usually complete in fromiabout 1 to about 15 hours at temperatures of from about 50 to about 125C. A

,A convenient method of conducting the reaction is to, mixthe reactants in a suitable solvent or diluent and heatgthe reacti m xt i fi a refiuk condenserfluntildthe "reaction is completel jThe reaction may be fconductedunder pressure, if desired. A suitable solvent mayf-be water alone or methanol; ethanol,- dioxane,

Cellosolve, I or g a mixture 'of these owe ts with each other or withfwater. "Although" Iusually ether of ethylene glycol), aliphatic alcohols,' l=

pyridine, etc. The compounds .are useful tor :a

' variety of '.purposes:'.as dyestuflf intermediates and .in the I preparation .of pharmaceuticals and resinous products.

The 3-ureido-1,2,4-triazoles used in the pipe-W ass of the present invention can be prepared by reacting an aoyl dicyandiam'ide with an acid salt of. hydrazine as shown in Example 2.

A very great number of 3-ureido-1,2,4-trlazoles can be employed :in' lthe reolctiom described here- :triazoie, i3-ureido 5. (:p-nfltrophenyl) 1,2 ,4 -tr1- azole, Q-Rureido -5 oearboxyphenyl) -1,2,4-triazole, 3 ureido-fiiphydroxyphenyh-1,2,4---triazole, land other alkyl, cycloa'llwl, and aryl 3- meidol,2,4-=triazoles. 1

In carrying out my invention, hydrolysis zmay be accomplished by the :use of conventional hydrolyningagents such :as strong mineral acids? hydrochloric, nitric, .sulhuic, phosphoric, and the like; or alkalis including sodium hydroxide,

-- potassium hydroxide, barium hydroxide, sodium -carbonate, potassium carbonate, :etc.

reaction between '3-'ureido -'1;2 ,4-triazoles dissolve the reactants beiorefheat g h 11 tion mixture; itf'i's not necessary '-that "they' be completely dissolved. 'If desired, one of thereactants' may be "dissolved inla' so'lve'ritand the o h ma n" add d. .vh e i wea e form.

"wh n "carrying out" the hydrolysis 1dr 1 3- ureido-1,2,4-triagole injziccordanCe with my invention, ammonia is evolved When acidjis used as the hydrolyzing agent, "the corresponding '3- amino- LgA-triazole acid salt i ,l ornred, When carrying out th hydrolysis' vvith alkali, anLacid salt of fthetriazole product; may: obtained by "the addition or acid to'thefreacted'mixturef";

'My invention Will now be illustrated in greater detail by means of the following speiiic examples in which representative amyl'anaaryi 3{ureido-1,2,4 triazoles 'are hydrolyzed and alkali -tdyield 3-arr'iino-5- alkyl "(andaryll- 1,2,4-triazines. It will be understood, of'course, that these examplesare'g'iven for purposes of illustrationandare motto be--,considered as limiting my invention to the particular details 1 described therein.

Filtration gave colorless, fine needles which de-" composed at 253254 C. A portion of the hydrochloride was dissolved in water, made alkaline with sodium hydroxide, and treated withexcess nitric acid. Filtration of the insoluble nitrate salt gave an amorphous solid decomposing at 208 C. Another portion of the'hydrochloride son; was

The

' triazole, its nitrate, and its hydrochloride given treated with excess ammonium hydroxide. free base was found to melt at 187-l88 C. a r I The melting points for 3-amino-5-phenyl-1,2,4-

above correspond to those shown in the literature. As final proof, a mixed melting point was made with a sample of 3-amino-5-phenyl-1,2,4-

triazole prepared by another method, and no depression in melting point was observed.

7 EXAMPLE; 2

3-cmino-5-phenyl-i,z,4-triazole To a solution of 16.5 g. of 97% sodium hydroxide in 100 cc. of water was added 42 g. of hydrazine dihydrochloride. This solution was then added to a'suspension of 37.6 g. of benzoyl di- EXAMPLE 4 3-amino-5-methyZ-1,2,4-triazole To a solution of 127.5 g. (3.0 mols) of 95% sodium hydroxide in 300 cc. of water was added 202 g. (1.43 mols) of 3-ureido-5-methyl-1,2,4- triazole. The resulting solution was refluxed for "3 hours; duringwhichtimEammonia was strongly evolved. I Decolorizing characoal "was added, and the solution filtered, neutralized with acetic acid and evaporated to dryness. The solid was excyandiamide in 250 cc. of methanol and the whole;

refluxed. Within 5 minutes of reflux, a solid cake,

of product had formed. Water was added, the mixture cooled, and the solid filtered, washed well with water and air dried. A quantitative yield of Other 3-ureido-5-(alkyl, cycloalkyl, and aryl) 1,2.4-triazoles may be prepared in like manner.

-A solution of 40.6 g. (0.20 mol) of 3-ureido-5- phenyl-l,2,4-triazole and 33 g. (0.50 mol) of 85% potassium hydroxide in 250 cc, of water was rea fluxed for 3 hours. during whichtime ammonia was strongly evolved. Addition of acetic acid to a small portion of the solution gave no precipitatate of starting material. The solution was treated with filter aidand Nuchar, filtered, and

cooled. Excess nitric 'acid was slowly added, causing evolution of carbon dioxide and precipitation of the insoluble nitrate. Filtration gave 43 g.,- or a crude yield of 96%, of a product dewater gave a'67.5% yield of 3-amino-5-phenyl- 1,2,4-triazolenitrate which decomposed at 208- 209 C.

EXAMPLE 3 3-amino-5-amyZ-1,2',4-tria2oZe To a solution of 32 g. (0.75 mol)-of 95%s0dium hydroxide in 250 cc. of water was added 69 g. (0.35 mol) of 3-ureido-5-n-amyl-1,2,4-triazole. The resulting .pale.yellow solution was refluxed for 7 hours. During this time the solution became colorless, and ammonia was evolved. Norite was added, thesolution filtered, and the colorless filtrate cooled and acidified with excess nitric acid.- Carbon dioxide was-strongly evolved,

and colorless, crystals, of 3-amino-5-n-amyl-1,2,4- triazole nitrate separated. The filtered solid was washed with a little water and acetone and'air dried. 'Decompbs ition' ofthe product occurred, whenza'sample was heated, at '138139 C.

composingat 205 C. Crystallization from hot 1,2;4-triazoles which comprises-heating together 3-ureido-5-phenyl-1,2,4-triazole was obtained "in which isa the groupconsisting .tracted vwith,boiling ethyl acetate and filtered from the sodium acetate. Evaporation of the ethyl acetatesolution gave 3-amino-5-methy1- 1g riazolel w EXAMPLE 5 I f E'wmiimi 5-heptadecyl-1,2,4-triazole A solution of 25.50 g. (0.60 mol) of sodium hydroxide in 500 cc. of 2-B alcohol was prepared and 107 ,g. (0 .2921mol) v of 3-ureidoe5-heptadecyl- 1,2,4g triazo1e added and v the. whole refluxed. The yellow .solution soonwjery slowly ,evolved ammonia, and solid (sodium carbonate) separated to produce. a 1 turbid solution..- Heating, wascontinued fonatotal-of 1 7 hour'sl, The mixture was then poured i'nto je .liters ,Iof cold water and, the soapy f solution acidified with acetic, acid. I The nearly colorlessprecipitate was filteredwashed with water, and dried in an oven at 65 C. The

somewhat waxy solid'weighed 97 g. and melted at -110". C. Thesolid' dissolved in dilute hydrochloric acidto produce a clear, soapy solution. Crystallization from a 50-50 ethanol-Cellosolve mixture gave 83 g. or an 87% purified yield ':of. colorless, "amorphous-appearing solid which melted, as before at 105'-*1'10 -C."

Iclaimz" "1. A' method of' preparing '3-"amino-1,2,'4-tri- .s: s wh ch ombf k ie elky i an a y .sjihe ionmilla:

prises heating a compound h flu, l ME I in which R. is a member of theg'roup consisting of alkyL- cycloa'lkyl'g and aryl radicals in'the presence of water and a-hydrolyzing agent. Y

. 1 2. A method of preparing .3 amino-'5 aryl"-1',2,4-

triazoles which comprises heating together water, a strong mineral acid and a 3-ureido-5-aryltriazoles which comprisesheatingtogether water, an alkali and a 3 -ureido-5 aryl-1;2,4-triazole.

4; A method of preparing- 3 amino-5ealkylwater, a strong mineral acidland?a=3f1ureido-5- alkyl-1.,2 ,4-'triazole.

1 5; A method of preparing '3-amino-5-alkyl- 1,2,4-triazoles which comprises heating 2 together water, an alkali and 5a; 3.-,ureido'-5-alkyl'-,1,2,4-triazole;

e. A method stealing s-amino-s-aryl rzatriazoles whicncomprises .mixingtogether in a water-miscible solvent and heating :within the 9. A method of preparing 3-amino-5-phenyl- 1,2,4-triazo1e which comprises mixing together in an aqueous reaction medium and heating sodium hydroxide and 3-ureido-5-phenyl-1,2,4-triazo1e.

10. A method of preparing 3-amino-5-alky1- 1,2,4-triazoles which comprises mixing together in an aqueous solvent a strong mineral acid with a 3-ureido-5-alkyl-1,2,4-triazole and heating the reaction mixture until a 3-amino-5-alky1-1,2,4-

10 triazole has been formed.

DONALD W. KAISER. 

